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July 28, 2017: The AAVSO Special Notice is being discontinued as of July 28, 2017. This notice - #430 - is the last Notice of the publication.

The type of information supplied in AAVSO Special Notices will now be supplied in the AAVSO Alert Notices and/or in the AAVSO online forums on Campaigns & Observation Reports, Time Sensitive Reports, and the other Variable Star Observing and Variable Star forums, as appropriate.

July 21, 2017: The following request for AAVSO assistance has been received from Denis Denisenko (Sternberg Astronomical Institute, Moscow State University) to help characterize "...the cataclysmic variable DDE 48 in Vulpecula. This CV belongs to the rare ER UMa subtype of dwarf novae, with only 6 other stars in VSX being classified as UGER. According to 2016-2017 observations by Nikolay Mishevskiy (MNIC) and Denis Denisenko (DDE), this variable is very active, with superoutbursts to magnitude V=15.4 occurring approximately once a month.

July 7, 2017: Roque Ruiz-Carmona (Ph.D. candidate, Institute of Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen, The Netherlands) has requested AAVSO assistance in determining the status of 20 eclipsing cataclysmic variables (CVs) in order to select one system in outburst for observation with the William Herschel Telescope (WHT) at La Palma, to detect and study spiral density waves in the system. The WHT observations will begin on 2017 July 11 UT.

The charts and sequences team has been busy over the last several months preparing new sequences for newly discovered objects and revised sequences intended to improve existing sequences. If you observe any of these objects please update your charts and/or sequences. A file in .xlsx format is attached below for your convenience.

The AAVSO Newsletter is a periodic, general forum that supports our various observing programs with lists of new targets, observing programming ideas, and general information that spans a wide area of interest. Guest writers contribute pieces that can range from current events to book reviews.